Sodium dichromate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The EU RAR (2005) reports the findings of a number of published tests of cytogenicity / clastogenicity performed with Cr (VI) compounds and incorporates the findings of previous reviews by the UK Health & Safety Executive (HSE; 1989) and the UK Institute of Occupational Health (IOH, 1997). Individual studies are of varying reliability but the overall conclusion (weight of evidence) is considered to be reliable.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

other: review

Title:

European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and potassium dichromate

Author:

European Chemicals Bureau

Year:

2005

Bibliographic source:

3rd. Priority List; Volume 53

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Cytogenicity Study

Principles of method if other than guideline:

The EU RAR summarises the findings of a number of cytogenicity studies performed to various non-standard designs.

GLP compliance:

no

Remarks:

largely older, literature studies

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Chromium trioxide

EC Number:

215-607-8

EC Name:

Chromium trioxide

Cas Number:

1333-82-0

Molecular formula:

CrO3

IUPAC Name:

Trioxochromium

Constituent 2

Reference substance name:

Sodium dichromate

EC Number:

234-190-3

EC Name:

Sodium dichromate

Cas Number:

10588-01-9

Molecular formula:

Cr2Na2O7

IUPAC Name:

sodium dichromate

Constituent 3

Reference substance name:

Sodium chromate

EC Number:

231-889-5

EC Name:

Sodium chromate

Cas Number:

7775-11-3

Molecular formula:

CrH2O4.2Na

IUPAC Name:

disodium dioxido(dioxo)chromium

Constituent 4

Reference substance name:

Potassium dichromate

EC Number:

231-906-6

EC Name:

Potassium dichromate

Cas Number:

7778-50-9

Molecular formula:

Cr2H2O7.2K

IUPAC Name:

potassium dichromate

Details on test material:

No further details are reported

Method

Target gene:

Not applicable - cytogenicity / clastogenicity assays

Species / strain

Species / strain / cell type:

other: various

Metabolic activation:

with and without

Metabolic activation system:

various

Test concentrations with justification for top dose:

Various

Vehicle / solvent:

Not reported for individual studies

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

Not reported for individual studies

Evaluation criteria:

Not reported for individual studies

Statistics:

Not reported for individual studies

Results and discussion

Test results

Species / strain:

other: various

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

The results of in vitro cytogenicity /clastogenicity / chromosomal aberration tests performed with the water-soluble Cr (VI) compounds in this group are invariably positive.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

The results of in vitro cytogenicity /clastogenicity / chromosomal aberration tests performed with the water-soluble Cr (VI) compounds in this group are invariably positive.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive weight of evidence

The results of numerous tests performed with water-soluble Cr (VI) compounds indicate that this group of compounds is clastogenic in vitro.

Executive summary:

There is a very large body of evidence indicating that the Cr (VI) ion in solution is directly clastogenic in vitro. This activity was diminished considerably by the presence of reducing agents, in the form of tissue S9 or S12 fractions, gastric juice or reducing agents such as glutathione, ascorbate or sulphite. These all serve to reduce Cr (VI) to Cr (III) outside the cell therefore greatly reducing entry of chromium into the cell.